A conventional meter box comprises an electric watt-hour meter installed within a meter socket. In a single-phase power system, the meter socket includes two power supply connectors that connect the power supply conductors to the meter and, similarly, two power load connectors that connect the power load conductors to the meter. In a three-phase power system, the meter socket includes three power supply connectors that connect the power supply conductors to the meter and, similarly, three power load connectors that connect the power load conductors to the meter. In both types of systems, electrical current flows from the electric power utility over the power supply conductors to the power supply connectors of the meter socket, through the meter, to the power load connectors of the meter socket and over the power load conductors to the customer premise.
In the United States, it is estimated that between one-half percent (0.5%) and three and one-half percent (3.5%) of electricity delivered by electric power utilities is lost to theft. In other countries with weaker governance factors, the rate of electricity theft is estimated to be as high as twenty percent (20%). There are a variety of ways in which energy thieves can tamper with different types of meter sockets and meters—both older electromechanical meters and newer electronic meters—in an effort to steal the electricity.
Meter sockets with older electromechanical meters can be tampered with in a number of ways. For example, energy thieves can attach magnets to the outside of the meter socket enclosure in order to interfere with the internal magnetic field and reduce the rotation of the disk within the meter. Energy thieves can also insert a device into the meter socket that acts as a brake to slow the meter from spinning. It is also possible to add dirt or liquid to cause rust in an effort to slow down the rotation of the meter. As yet another example, energy thieves can remove the meter from the meter socket and re-install the meter in an inverted position so that the meter runs backwards. Further, energy thieves can tap into the power supply at the power supply connectors of the meter socket before the electrical current flows through the meter in order to run large energy loads with un-metered power.
Some of the tampering methods available for electromechanical meters have been eliminated with the implementation of advanced metering infrastructure (AMI). AMI is an integrated system of electronic “smart” meters and communication networks that enables two-way communication between the electric power utility and the electronic meters. Many AMI meters contain sensors that detect unusual external electrical or magnetic fields, which eliminates the use of magnets as an effective tampering method. Also, the method of inverting the meter is not effective insofar as many AMI meters detect the removal of the meter from the power supply connectors of the meter socket and/or detect the reversed flow of electrical current. Upon detection of any of these tampering conditions, AMI meters may log the event and preferably send an alarm to the electric power utility over an established communication network when power is available, e.g., when the meter is installed back on the power supply connectors of the meter socket.
While many forms of tampering are no longer possible with AMI meters, there are still methods that energy thieves can employ to steal electricity. For example, the method of bypassing the meter by tapping into the power supply at the power supply connectors of the meter socket is possible not just for older electromechanical meters, but also for new AMI meters. As such, if energy thieves are able to gain access to the inside of the meter socket, whether by removing the cover of the meter socket enclosure or drilling a hole through the meter socket enclosure, it is possible to run large energy loads with un-metered power.